1. Technical Field
The present invention relates to novel polyimidothioethers-inorganic nanoparticle hybrid material. More particularly, the present invention relates to polyimidothioethers-inorganic nanoparticle hybrid material, intermediate thereof and their preparation, wherein the hybrid material exhibits good surface planarity, thermal dimensional stability, tunable refractive index, and high optical transparency upon forming into films.
2. Description of Related Art
High refractive index polymers have been widely proposed in recent years for their potential in advanced optoelectronic applications. In addition to the basic parameter of the refractive index, the other ones such as birefringence, Abbe's number, optical transparency, proccessability, and thermal stability are often taken into consideration. Regarding the encapsulants for organic light-emitting diodes (OLEDs), commercial applications require materials with high refractive index, low birefringence, high optical transparency, and a long-term ultraviolet light and thermal stability. Therefore, to achieve a good combination of the above-mentioned parameters is a crucial and on-going issue (J. G. Liu and M. Ueda, J. Mater. Chem., 2009, 19, 8907). Recently, systematic work by Ueda revealed the influence of sulfur groups and related structures on the refractive index and optical dispersion of the resulted polyimides (C. A. Terraza, J. G. Liu, Y. Nakamura, Y. Shibasaki, S. Ando and M. Ueda, J. Polym. Sci., Part A: Polym. Chem., 2008, 46, 1510; N. H. You, Y. Suzuki, D. Yorifuji, S. Ando and M. Ueda, Macromolecules, 2008, 41, 6361; J. G. Liu, Y. Nakamura, Y. Shibasaki, S. Ando and M. Ueda, Macromolecules, 2007, 40, 4614;  J. G. Liu, Y. Nakamura, Y. Suzuki, Y. Shibasaki, S. Ando and M. Ueda, Macromolecules, 2007, 40, 7902). The incorporation of sulfur atom into polymer systems could enhance the refractive index and optical transparency due to its large atomic refraction. It is also well known that the thermoset polyimides derived from bismaleimides (BMIs) exhibit excellent thermal and mechanical properties, thus made them extremely popular for advanced composites and electronics.
In addition, polymer-inorganic hybrid materials had recently attracted considerable interest owing to their enhanced mechanical, thermal, magnetic, optical, electronic, and optoelectronic properties when compared to the corresponding individual polymer or inorganic component. Chemical methods based on in-situ sol-gel hybridization approach made it possible to manipulate the organic/inorganic interfacial interactions at various molecular and nanometer length scales, resulting in homogeneous structures and thus overcoming the problem of nanoparticle agglomeration.
Based on the above mentioned industrial situation, the inventors of the present invention have investigated how to produce polyimides-inorganic nanoparticle hybrid material having optical transparency and thermoplasticity from BMI type monomer, and thus completed the present invention.